1. Technical Field of the Invention
The present application is directed to an automatic suction type transfer apparatus and method for transferring workpieces of limp material. More specifically, the transfer apparatus of the present application provides for transfer of a workpiece of a limp material (also known as a limp workpiece) from one conveyer to another without losing its orientation. The transfer apparatus and method enables transfer of a limp workpiece between conveyors operating or conveying at different speeds. Further, the transfer apparatus transfers the limp workpiece from a first conveyor to a second conveyor by creating a pressure differential and eliminates wrinkles in at least a portion of the limp workpiece during the aforementioned transfer.
2. Description of Related Art
Known transfer apparatuses and methods enabled transfer of workpieces from one conveyor to another or enabled removal and stacking of workpieces previously traveling on a particular conveyor. The apparatus for conveying the workpiece on a type of transfer apparatus, or for removing workpieces from a conveyor included vacuum type apparatuses which used vacuum suction to contact the workpiece and to remove it from the conveyor.
Problems existed, however, when the workpiece was one of a limp material, also known as a limp workpiece. Such materials included fabrics for example. When transferring a fabric from one conveyor to another, wrinkles tended to develop. Therefore, separate processes were necessary subsequent to the transfer of the workpiece, to smooth out any wrinkles obtained during the transfer process. The vacuum suction devices, in particular, tended to create wrinkles when utilized in conjunction with a limp workpiece.
Further problems existed when attempting to transfer a workpiece from a first conveyor moving at a first speed to a second conveyor moving at a second speed, different from the first speed. Differences in speeds were further complicated when the transfer apparatus was operating or conveying at a speed different from the speed of the first and/or second conveyor.
The aforementioned problems of transferring a workpiece between two conveyors operating at different speeds, and transferring utilizing a transfer apparatus operating at a speed different from the first conveyor and/or the second conveyor, were further complicated when the workpiece is a limp workpiece. The difference in speeds tended to create wrinkles in the workpiece, which again had to be smoothed out subsequent to the transfer of the limp material or workpiece to the second conveyor.